Leveling system for portable work platforms

ABSTRACT

The claimed work platform system, alternatively dubbed by the inventor as “Miniscaffold”, provides a compact, versatile, and portable method of supporting workers engaged in various elevated construction or maintenance activities. The claimed work platform rides upon a number of locking floor casters. Each floor caster is mounted to a removable, telescoping support which may be readily relocated inward to accommodate access through narrow aisles or outward to enhance the platform&#39;s stability. 
     Each telescoping support is also fitted with an individual jack mechanism to compensate for the inevitable variations in ground or floor elevation typical at construction or work sites. 
     The “Miniscaffold” is also constructed from interlocking square tube members which enhance the work platform&#39;s stability and thus eliminate the obtrusive and cumbersome diagonal supports found on most scaffolding.

BACKGROUND

It is common practice for persons in construction, building, and maintenance trades to use work platforms and scaffolding to access elevated work areas. The safety and productivity of workers using these portable work platforms or scaffolds requires that the platforms or scaffolds be physically stable, easy to position and level, and readily moved from place to place.

The majority of portable work platforms or scaffolds currently in use in the construction and maintenance trades are supported by four legs or points of contact with the ground. In some instances, these legs to be fitted with stem casters to facilitate relocation between workplaces.

The ground or floor surface at many construction sites and other work locations is often irregular and uneven. In current field practice, significant time and effort is required to level the scaffolding by placing wooden blocks or other cribbage under the platform support legs, wheels, or casters. It is common for many portable scaffolds, such as those fitted with wheels, to be inadequately blocked or leveled due to the unavailability of proper cribbage and/or hasty installation.

Often those best points of support (i.e., solid, level surfaces) for the work platform do not correspond with the location of the work platform's vertical support elements. This leads the users to either move the platform to a less than ideal location to perform the overhead task, or tolerate an unstable (and often unsafe) work platform.

It is common practice for existing scaffolding to be constructed from tubular structural members. The geometry of these traditional tubular scaffolding members provide high load bearing capacities but do not provide torsional rigidity. As a result, traditional scaffolding must be fitted with diagonal braces. These diagonal braces often interfere with tasks such as painting, tuck pointing or other maintenance or construction activities.

In many applications the use of scaffolding or work platforms could allow workers to perform their tasks more efficiently than is possible working from an extension or step ladder. But scaffolding is not used because traditional scaffolding is too large or cumbersome to fit through a narrow door way or similar obstruction. Valuable work time is often wasted ascending, descending and repositioning ladders.

DESCRIPTION OF DRAWINGS An Isometric View of Jack Assembly Drawing One

An isometric assembly drawing which depicts a unique and original arrangement of a stabilizing jack, a locking caster, and perforated mounting tube.

An Isometric View of Jack Assemblies as Inserted into Carriage Drawing Two

An isometric assembly drawing depicting (four) mechanical jack assemblies as detailed in “Drawing One” are in various states of insertion into a carriage so as to make a unique leveling system for supporting a scaffold or work platform.

An Oblique View of Leveling System Upon Irregular Terrain Drawing Three

An oblique view drawing depicting the ability of the claimed leveling system for a scaffold or work platform to compensate for irregularities in floor elevation or ground conditions.

An Orthographic View of Leveling System Upon Irregular Terrain Drawing Four

A front view orthographic drawing depicting the ability of the claimed leveling system for a scaffold or work platform to compensate for irregularities in floor elevation or ground conditions.

An Isometric Detail View of Platform Elements and their Engagement Drawing Five

An isometric assembly drawing which provides a detailed view of the claimed engagement of square and rectangular tube elements so as to form the structure of the claimed platform.

A Partially Exploded Isometric View of Work Platform and Leveling System Drawing Six

An isometric assembly drawing depicting work platform and leveling system elements in various states of engagement to accommodate various stability and/or spatial constraints.

An Isometric View of Fully Assembled Work Platform and Leveling System Drawing Seven

An isometric assembly drawing depicting a typical arrangement of the fully assembled scaffold or work platform, carriage, and leveling system. In the depicted ‘narrow’ configuration, the work platform would easily negotiate a constricted hallway or other area of limited accessibility.

EXPLANATION OF DRAWINGS

“Item A”—The “jack body” or stationary portion of a typical stabilizing jack, such as those often used to support or lift the tongue of an automotive trailer. (See note below)

“Item B”—The “telescoping foot” of a typical stabilizing jack assembly, such as those often used to support or lift the tongue of an automotive trailer.

“Item C”—The “hand crank” as typically rotated by the user to raise or lower a stabilizing jack, with major components depicted in entirety as items “A”, “B”, and “C”.

“Item D”—A typical commercially available “fully locking floor caster”. When activated by the user, the caster's integral brake prevents rotation of both the wheel as well as rotation of the caster.

“Item E”—A “jack attachment tube” consists of a length of commercially available steel or aluminum box tube as extruded in a square or rectangular hollow profile.

“Item F”—“Locating holes” or similar through perforations as punched or drilled through item “E” which allows the insertion of pins or similar retaining hardware.

“Item G”—A ‘carriage’ which supports the work platform which is fabricated from commercially available steel or aluminum box tube as extruded in a square or rectangular hollow profile.

“Item H”—Modular, interchangeable ‘H members’ constructed from square or rectangular tubing which form the vertical elements and ends of the portable scaffold or work platform.

“Item I”—Modular, interchangeable ‘I members’ constructed from square or rectangular tubing which form the vertical elements and sides of the portable scaffold or work platform.

“Item J”—‘Receivers’ or similar openings at each end and on the major axis of the ‘carriage’, (item G).

“Item K”—‘Receivers’ or similar openings at each side and on the minor axis of the ‘carriage’, (item G).

“Item L”—‘Locating holes’ or similar through perforations as punched or drilled through the carriage, (item G) which allows the insertion of ‘retaining pins’ (item M) or similar retaining hardware.

“Item M”—A commercially available ‘retaining pin’, which could be a hitch pin, device pin, spring pin or similar common means of attachment.

Note: The ‘stabilizing jack’ assembly (summation of items A, B, and C), ‘locking caster’ (item D), and ‘retaining pin’ (item L) depicted herein are common, commercially available components. These items are not claimed, but rather their use in part of a unique and original combination which, when incorporated together with other depicted components, provides an improved method of leveling and stabilizing portable work platforms.

Description of the Claim and Invention

001) It is common and accepted practice in the building, maintenance, and construction trades to use portable work platforms or scaffolds to perform tasks in elevated locations.

002) It is common for the floor, ground surface, or other environmental terrain of many construction and maintenance sites to be irregular, rough, or strewn with debris or other errant, random objects.

003) It is desirable that workers engaged in construction and maintenance trades be able to readily move portable scaffolds or work platforms from one location to another in order to expeditiously perform various tasks at various locations.

004) It is common and accepted current practice to fit wheels and stem casters to the vertical members of certain existing, commercially available scaffolds and work platforms to accommodate locomotion as outlined in “paragraph 003”.

005) It is advantageous that those engaged in various construction and maintenance trades be provided with portable scaffolds and work platforms which are more stable than those currently commercially available through an improved and more versatile means of leveling and supporting such work platforms.

006) The Inventor claims that a substantial improvement over the current art and practice of manufacturing and configuring portable scaffolds and work platforms is achieved when certain jack, caster, and other commercially available components are combined in his unique and original modular work platform as described herein.

007) Please reference “Drawing One” which depicts a typical, commercially available ‘stabilizing jack’ assembly consisting of three principle external components; a fixed body “A”, a telescoping member “B”, and a hand crank “C”. A commercially available ‘locking floor caster’, “D”, is bolted or similarly attached to the lower, telescoping portion of the stabilizing jack “B”.

008) The inventor's “Claim I”, to ‘provide convenient movement of the portable scaffold or work platform’ is achieved by combining the jack assembly (sum of items “A”, “B”, and “C”) with that of the ‘locking floor caster’, item “D” as described above in “paragraph 007”.

009) The benefit of improved platform stability as described in “paragraph 005” is enhanced by incorporation of the locking feature commonly found on certain commercially available ‘locking floor casters’, “D”. ‘Locking floor casters’ are integrated with the jack assemblies as described in “paragraph 008”. This feature allows the user to set the caster brakes when at the desired work location. Upon completing the task, the user releases the caster brake to facilitate rolling the entire work platform to another desired location.

010) The body of the stabilizing jack “A” is welded, or similarly securely joined, to a length of steel box tube or similar square or rectangular structural material to provide a ‘jack mounting tube’ which is depicted as item “E”.

011) Each jack mounting tube, “E” is perforated on its vertical axis through both faces of the square or rectangular tubing. These perforations, depicted as item “F” are located at one or more locations along the length of the jack mounting tube. In “Drawing One”, the perforations “F” are depicted at three locations on each jack mounting tube “E”.

012) Please reference “Drawing Two” which depicts a ‘carriage’ as item “G”. The carriage frame is fabricated from steel box tube or similar hollow rectangular or square tubing in such a manner that openings, or ‘receivers’ as depicted as items “J” and “K” are located at each corner of the carriage, “G”. Item “J” receivers are located on the major axis of the carriage while item “K” receivers are located on the minor axis of the carriage.

013) A running fit is formed between the internal opening of each receiver, “J” and “K” and the outside faces of each jack mounting tube, item “E”, thus allowing the engagement of a jack mounting tube “E” into any desired receiver “J” or “K”.

014) The Inventor's “Claim II”, to ‘readily change or adjust the position of each point of support of the portable scaffold or platform so as to improve access and transit through narrow doorways, aisles, or other physical obstacles’ is achieved when the user elects to insert the jack mounting tubes “E” into the major axis receivers “J” in the method as described in paragraphs “012” and “013”. Thus configured by the user, the portable scaffold assumes a narrow profile and is easily maneuvered through a narrow doorway or aisle, as depicted in “Drawing Seven”.

015) The inventor's “Claim III”, to ‘Readily change or adjust the position of each point of support of the portable scaffold so to improve platform stability is achieved when the user elects to insert the jack mounting tubes “E” into the minor axis receivers “K” in the method as described in paragraphs “012” and “013”. Thus configured by the user, the portable scaffold assumes a wide profile and provides the stability required by workers to safely ascend the platform.

016) The Inventor's “Claim IV” provides an advantage to ‘compensate for variations in floor elevation or obstructions beneath the portable scaffold or work platform’. For example, in an environment of irregular clutter, mud holes, or other random obstacles, the user may choose to insert the “E” portion of certain jack assemblies into any combination of receivers “J” and/or “K” which correspond with those areas perceived by the user to offer the best support.

017) “Drawing Three” provides an oblique view of a configuration of the claimed work platform leveling system in which the telescoping portion of a stabilizing jack assembly “B-1” has been extended by the user to compensate for an obstacle while the remaining jack assemblies “B” remain in an retracted configuration.

018) “Drawing Four” provides an orthographic front view of the claimed work platform leveling system in which the telescoping portion of a stabilizing jack assembly “B-1” has been extended by the user to compensate for an obstacle while the remaining jack assemblies “B” remain in an retracted configuration.

019) The carriage, “G”, is perforated on a vertical axis with a through holes “L” at points adjacent to each major axis receiver “J”, and each minor axis receiver “K”. These holes lie on a shared centerline with the jack attachment tubes, “E”.

020) After inserting a jack attachment tube “E” at a desired location as described in paragraphs 014, 015, or 016, the user inserts a retaining pin “L” to secure the jack attachment tube “E”, and assure platform stability.

021) In summary, the user may elect to readily adjust the elevation of each corner of the portable scaffold or work platform by rotating the jack ‘hand crank “C” and readily adjust the location of support for the platform by selecting an appropriate receiver “J” and/or “K” into which to insert each jack attachment tube, “E”.

022) It is common and accepted practice for existing, commercially available scaffolds and portable work platforms to be fitted with stem casters or wheels. However, these casters cannot be readily removed or relocated unless the scaffolding is disassembled.

023) The Inventor's “Claim V” to ‘allow relocation of each individual point of support without requiring scaffold disassembly or causing the platform to tip or become temporarily unstable’ is achieved by a user procedure as described in the following paragraphs “024” through, “029”.

024) Assuming jack assemblies positioned in locations as depicted in “Drawing Six”, the operator may wish to remove and relocate the ‘south’ stabilizing jack assembly. The user would operate the ‘hand crank’ “C” on the ‘north’ jack assembly so as to retract the telescoping foot “B”.

025) Following retraction of the ‘north’ jack assembly as described in “paragraph 023”, the weight of the portable scaffold or work platform is primarily upon the ‘east’ and ‘west’ jack assemblies.

026) The operator may then elect to remove the retaining pin “M” on the ‘south’ jack assembly and withdraw the jack assembly and jack attachment tube “E” from the receiver “J”.

027) The operator may insert the jack attachment tube “E” into the adjacent receiver “K” on carriage “G”. The operator subsequently reinserts retaining pin “M” through perforation “L”.

028) Following the procedures outlined in paragraphs “024” through “027”, the user may elect to adjust the elevations of the north and south jacks until the desired platform level is achieved.

029) Alternatively, the operator may elect to repeat the relocation procedure as described in paragraphs “024” through “028” at one or more of the remaining corners of the carriage “G” until the desired balance, stability and/or width of the platform is achieved.

030) It is the current and accepted practice to utilize round tubing as the primary structural elements in commercially available scaffolding and work platforms. While round steel pipe is typically less expensive than similar gauge square or rectangular tubing, round tubing does not provide offer the torsional rigidity when inserted within another tube as can be obtained by two intersecting lengths of square tubing.

031) Please reference “Drawing Five”. Scaffolding components are assembled to the carriage to form a useful work platform. The ends of the platform include ‘H-members’ as depicted as item “H”. The horizontal elements of the platform are comprised of ‘cross members’ as depicted as item “I”.

032) The engagement of the claimed square or rectangular geometry of the mating areas of ‘H-members’ “H” with the square or rectangular geometry or the mating areas of ‘cross members’ “I”, and ‘carriage’ “G” provides a substantial increase in torsional rigidity to the assembled platform.

033) The Inventor's “Claim VI” of ‘eliminating diagonal supports which obstruct and interfere with tasks’ is realized by the utilization of square and rectangular elements as described in paragraphs “031” and “032” in lieu of round tubing as is the current practice and described in “paragraph 030”.

034) The Inventor's “Claim VII” of ‘Providing a simple and reliable method of dismantling and reassembling the portable scaffold or work platform for compact transportation or storage’ is realized by the use of modular, interchangeable components and interlocking design as depicted in Drawing Six and Drawing Seven. 

I) Provide convenient movement of the portable scaffold or work platform between work sites upon locking caster wheels. II) Readily change or adjust the position of each point of support of the portable scaffold or platform so to improve access and transit through narrow doorways, aisles, or other physical obstacles. III) Readily change or adjust the position of each point of support of the portable scaffold so to optimize or improve platform stability. IV) Provide hand-operated jacks to compensate for variations in floor elevation or obstructions beneath the portable scaffold or work platform. V) Provide an interlocking structural design to allow relocation of each individual points of support without requiring scaffold disassembly or causing the platform to tip or become temporarily unstable. VI) Eliminate the need for diagonal supports which obstruct and interfere with tasks being performed by users of the portable scaffold or work platform. VII) Provide a simple and reliable method of dismantling and reassembling the portable scaffold or work platform for compact transportation or storage. 